Field of the Invention
The present invention relates to a holding device, a lithography apparatus and a method for manufacturing an item.
Description of the Related Art
There is a case where an exposure apparatus used in a process of manufacturing a semiconductor device or the like is provided with a substrate having surface irregularities or warpage. When the substrate is held by vacuum suction, there is a possibility that the suction force will decrease as a result of air leakage occurring due to the warpage of the peripheral edge of the substrate. In addition, when a pattern is transferred onto the substrate in a state where the suction force is small, and the surface irregularities or the warpage of the substrate is large, there is a possibility that the transferred pattern will become deformed resulting in a poor yield of the device manufactured.
Japanese Patent Laid-Open No. 2002-217276 discloses a holding device in which a seal member, which is an elastic body, is disposed over the outer periphery of a substrate-holding surface. As a result of the seal member deforming in such a manner as to follow the shape of the peripheral edge of a substrate, the possibility of the occurrence of air leakage from a space between the substrate and the substrate-holding surface is reduced, so that a suction force is increased. The substrate-holding surface of the holding device includes a plate-shaped member that has intake holes, which have the same size and the same shape and which are arranged at a certain pitch.
Like the holding device described in Japanese Patent Laid-Open No. 2002-217276, when air suction is performed by using all the intake holes, which have the same size and the same shape and which are arranged at a certain pitch, at the same time, the distribution of a negative pressure at the substrate-holding surface is uniform, or the negative pressure at the peripheral edge is smaller than that at the other portions. In view of the fact that there have been more cases where a substrate that has been largely deformed (e.g., largely warped) is transported into an exposure apparatus along with the recent increase in the variety of processes for manufacturing devices, there is a possibility that it may be difficult to correct the warpage of the peripheral edge of a substrate due to a small suction force at the peripheral edge of the substrate.